Fact: A standing car- Fuel loaded, continuously looses its fuel owing to vaporisation property of the fuel.
Idea: Lets not allow that! 😀
Method:
I suggest we have a expandible Poly-Ethylene (high grade Plastic) forming a baloon like structure inside our fuel tank, the sack-type-balloon will inflate enough to allow a full tank fuel volume, and deflate with fuel-depletion (fairly elastic, I mean to say)
The balloon sack will have
–vent– (for venting/only at filling time),
–filling end ( for fuel in )
–discharge end (fuel out of fuel tank- to fuel pump/carb)
The tendency of the balloon will be to empty its contents, hence keeping the fuel under slight positive pressure at all times.
The tank can still be stock!
I am making some drawing of the same. (simplified)
Care.
Ace.